RT Journal Article
SR Electronic
T1 Copenhagen Rats Display Dominantly Inherited Yet Non-uniform Resistance to Spontaneous, Radiation-induced, and Chemically-induced Mammary Carcinogenesis
JF Anticancer Research
JO Anticancer Res
FD International Institute of Anticancer Research
SP 2415
OP 2423
DO 10.21873/anticanres.15720
VO 42
IS 5
A1 MAYUMI NISHIMURA
A1 TATSUHIKO IMAOKA
A1 KAZUHIRO DAINO
A1 YUKIKO NISHIMURA
A1 TOSHIAKI KOKUBO
A1 MASARU TAKABATAKE
A1 SHIZUKO KAKINUMA
A1 YOSHIYA SHIMADA
YR 2022
UL http://ar.iiarjournals.org/content/42/5/2415.abstract
AB Background/Aim: Genetic and environmental factors interact to dictate the risk of cancer, and animal models are expected to provide avenues for identifying such interactions. The aim of the study was to clarify the genetic susceptibility of Copenhagen rats to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis. Materials and Methods: Female Copenhagen and Sprague– Dawley rats and their F1 hybrids were subjected at age 7 weeks to γ-irradiation or intraperitoneal injection with 1-methyl-1-nitrosourea or were not treated, and palpable mammary tumours were diagnosed histologically. Data were pooled with previous data acquired for both nontreated and irradiated Sprague–Dawley rats. Results: Radiation and 1-methyl-1-nitrosourea both significantly increased the incidence of mammary cancer in all strains. Copenhagen and F1 rats displayed a significantly lower incidence than Sprague–Dawley rats in all groups, with relatively higher incidence after irradiation. F1 rats exhibited significantly higher mammary cancer incidence than Copenhagen rats in the nontreated, but not the treated, groups. The interaction of the strain and exposure effects was suggested to be quasi-multiplicative. Conclusion: Copenhagen rats display non-uniform resistance to spontaneous, radiation-induced, and chemically-induced mammary carcinogenesis with dominant inheritance over Sprague–Dawley rats.